DOCSLIB.ORG

Hey, R.N., E. Baker, D. Bohnenstiehl, G. Massoth, M

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Hey, R.N., E. Baker, D. Bohnenstiehl, G. Massoth, M Article Geochemistry 3 Volume 5, Number 12 Geophysics 15 December 2004 Q12007, doi:10.1029/2004GC000764 GeosystemsG G ISSN: 1525-2027 AN ELECTRONIC JOURNAL OF THE EARTH SCIENCES Published by AGU and the Geochemical Society Tectonic//volcanic segmentation and controls on hydrothermal venting along Earth’s fastest seafloor spreading system, EPR 27°–32°S Richard Hey School of Ocean and Earth Science and Technology, University of Hawaii, 2525 Correa Road, Honolulu, Hawaii 96822, USA ([email protected]) Edward Baker NOAA/Pacific Marine Environmental Laboratory, 7600 Sand Point Way N.E., Seattle, Washington 98115-0070, USA DelWayne Bohnenstiehl Lamont-Doherty Earth Observatory of Columbia University, 61 Route 9W, Palisades, New York 10964, USA Gary Massoth Institute of Geological and Nuclear Sciences, Ltd., 30 Gracefield Road, P.O. Box 31-312, Lower Hutt, New Zealand Martin Kleinrock Joint Oceanographic Institutions, Inc., 1201 New York Ave, NW, Suite 400, Washington, DC 20005, USA Fernando Martinez School of Ocean and Earth Science and Technology, University of Hawaii, 2525 Correa Road, Honolulu, Hawaii 96822, USA David Naar College of Marine Science, University of South Florida, 140 Seventh Avenue South, St. Petersburg, Florida 33701- 5016, USA Debra Pardee School of Ocean and Earth Science and Technology, University of Hawaii, 2525 Correa Road, Honolulu, Hawaii 96822, USA Now at URS Corporation, 615 Piikoi Street, Suite 900, Honolulu, Hawaii 96814, USA John Lupton NOAA/Pacific Marine Environmental Laboratory, 2115 SE OSU Drive, Newport, Oregon 97365, USA Richard Feely NOAA/Pacific Marine Environmental Laboratory, 7600 Sand Point Way N.E., Seattle, Washington 98115-0070, USA Jim Gharib School of Ocean and Earth Science and Technology, University of Hawaii, 2525 Correa Road, Honolulu, Hawaii 96822, USA Joe Resing NOAA/Pacific Marine Environmental Laboratory, 7600 Sand Point Way N.E., Seattle, Washington 98115-0070, USA Also at Joint Institute for the Study of the Atmosphere and the Ocean, University of Washington, Seattle, Washington, USA Copyright 2004 by the American Geophysical Union 1 of 32 Geochemistry 3 hey et al.: segmentation along the epr Geophysics 10.1029/2004GC000764 Geosystems G Cristian Rodrigo Servicio Hidrografico y Oceanografico de la Armada de Chile, Errazuriz 232 Playa Ancha, Valparaiso, Chile Francis Sansone School of Ocean and Earth Science and Technology, University of Hawaii, 2525 Correa Road, Honolulu, Hawaii 96822, USA Sharon Walker NOAA/Pacific Marine Environmental Laboratory, 7600 Sand Point Way N.E., Seattle, Washington 98115-0070, USA [1] We have collected 12 kHz SeaBeam bathymetry and 120 kHz DSL-120 side-scan sonar and bathymetry data to determine the tectonic and volcanic segmentation along the fastest spreading (150 km/Myr) part of the global mid-ocean ridge system, the southern East Pacific Rise between the Easter and Juan Fernandez microplates. This area is presently reorganizing by large-scale dueling rift propagation and possible protomicroplate tectonics. Fracture patterns observed in the side-scan data define structural segmentation scales along these ridge segments. These sometimes, but not always, correlate with linear volcanic systems defining segmentation in the SeaBeam data. Some of the subsegments behave cohesively, with in-phase tectonic activity, while fundamental discontinuities occur between other subsegments. We also collected hydrothermal plume data using sensors mounted on the DSL-120 instrument package, as well as CTDO tow-yos, to determine detailed structural and volcanic controls on the hydrothermal vent pattern observed along 600 km of the Pacific-Nazca axis. Here we report the first rigorous correlation between coregistered hydrothermal plume and high-resolution marine geophysical data on similar scales and over multisegment distances. Major plume concentrations were usually found where axial inflation was relatively high and fracture density was relatively low. These correlations suggest that hydrothermal venting is most active where the apparent magmatic budget is greatest, resulting in recent eruptions that have paved over the neovolcanic zone. Areas of voluminous acoustically dark young lava flows produced from recent fissure eruptions correlate with many of the major hydrothermal vent areas. Increased crustal permeability, as gauged by increased fracture density, does not enhance hydrothermal venting in this area. Axial summit troughs and graben are rare, probably because of frequent volcanic resurfacing in this superfast spreading environment, and are not good predictors of hydrothermal activity here. Many of the hydrothermal areas are found in inflated areas near the ends of segments, suggesting that abundant magma is being supplied to these areas. Components: 15,313 words, 12 figures, 1 table. Keywords: seafloor spreading; mid-ocean ridges; hydrothermal plumes. Index Terms: 3035 Marine Geology and Geophysics: Midocean ridge processes; 3045 Marine Geology and Geophysics: Seafloor morphology and bottom photography; 3094 Marine Geology and Geophysics: Instruments and techniques; 4832 Oceanography: Biological and Chemical: Hydrothermal systems; 8150 Tectonophysics: Plate boundary—general (3040) Received 25 May 2004; Revised 3 September 2004; Accepted 21 October 2004; Published 15 December 2004. Hey, R., et al. (2004), Tectonic/volcanic segmentation and controls on hydrothermal venting along Earth’s fastest seafloor spreading system, EPR 27°–32°S, Geochem. Geophys. Geosyst., 5, Q12007, doi:10.1029/2004GC000764. 1. Introduction [e.g., DeMets et al., 1990, 1994]. Here we describe the tectonic and volcanic segmentation [2] Earth’s fastest present-day seafloor spread- along the fastest spreading part of this ridge, ing, as measured by magnetic anomalies, and discuss detailed structural and volcanic occurs along the southern East Pacific Rise controls on the hydrothermal vent pattern ob- (EPR), along the Pacific-Nazca plate boundary served along 600 km of the southern EPR 2of32 Geochemistry 3 hey et al.: segmentation along the epr Geophysics 10.1029/2004GC000764 Geosystems G nates, with even the intratransform spreading center patterns predictable from known changes in plate motion [Searle, 1983; Fox and Gallo, 1984; Lonsdale, 1989]. In contrast, the entire part of the Pacific-Nazca boundary spreading faster than 142 km/Myr is reorganizing by propagating rift and microplate tectonics [Naar and Hey, 1989a]. At these faster spreading rates, detailed swath mapping has shown there are no transform faults, but rather various nontransform offsets, including he 21°S dueling propagators [Macdonald et al., 1988a], the Easter and Juan Fernandez micro- plates [Hey et al., 1985; Searle et al., 1989; Naar and Hey, 1991; Larson et al., 1992; Rusby and Searle, 1995; Bird et al., 1998] and the giant dueling propagators between these microplates [Hey et al., 1995; Korenaga and Hey, 1996]. Transform faults do not occur again (other than transient ones on the slower spreading microplate boundaries) until the spreading rate drops at the triple junction south of the Juan Fernandez micro- plate (Figure 1). [4] The spreading rates in Figure 1 [from Hey et al., 1995] were calculated using the revised astronomically calibrated magnetic timescale [Shackleton et al., 1990; Hilgen, 1991] to modify the Naar and Hey [1989b] Pacific-Nazca Brunhes pole. This pole was constrained by EPR magnetic anomaly data collected too late for the NUVEL-1 compilation, and so, although similar, is an im- provement to the best-fitting PAC-NAZ pole from NUVEL-1 [DeMets et al., 1990]. NUVEL-1A [DeMets et al., 1994] also uses the revised time- scale, but is a global plate motion model, contam- inated by errors elsewhere, that predicts faster spreading than observed along the Pacific-Nazca boundary. In addition to fitting the new data better along the fastest part of this ridge, the Hey et al. [1995] pole (48.1°N, 90.5°W, 1.35°/Myr) also Figure 1. Location map and spreading rates from Hey provides a better fit to the 18°–19°S EPR data than et al. [1995]. Light lines are mid-ocean ridges; those the NUVEL models [Cormier and Macdonald, with arrows are propagating. Heavy straight lines are 1994, Figure 13]. Thus the spreading rates shown transform faults. Box surrounds axes surveyed. in Figure 1 are the most accurate currently avail- able for this region, and a fundamental change in plate boundary behavior occurs between spread- (Baker et al. [2002] and new results reported ing (whole) rates of 136 and 142 km/Myr, which here). we use to define a distinction between fast and ‘‘superfast’’ spreading behavior. We prefer this [3] Figure 1 shows that a qualitative change in terminology to that including slower spreading EPR plate boundary geometry occurs somewhere areassuchasthe17°SMELTarea(140 km between the Garrett transform fault at 13°S and Myr) in an ‘‘ultrafast’’ spreading category, espe- the dueling propagators near 21°S. Between the cially as Wilson [1996] has shown there were faster Garrett and the Pacific-Nazca-Cocos triple junc- spreading rates in the Miocene on the Pacific- tion the usual ridge/transform geometry domi- Cocos ridge. 3of32 Geochemistry 3 hey et al.: segmentation along the epr Geophysics 10.1029/2004GC000764 Geosystems G [5] Here we document both large-scale and finer- high side-scan backscatter, and dark/black areas are scale segmentation patterns along this fastest low backscatter or acoustic shadows). Due to the spreading ridge based on new SeaBeam and subjectivity associated with defining the center
Load more

Recommended publications
  • Propagating Rifts in the North Fiji Basin (Southwest Pacific)
    Propagating rifts in the North Fiji Basin (southwest Pacific) Giovanni de Alteriis Geomare, Istituto di Geologia Marina-CNR, Via Vespucci 9, 80142 Napoli, Italia, and IFREMER, Brest, France Etienne Ruellan CNRS, Institut de Géodynamique, Rue A. Einstein, Sophia Antipolis, 06560 Valbonne, France Hétène Ondréas61106 1 IFREMER' Centre de Brest' B p- 70' 29280' plouzané cédex. France Valérie Bendel Eulàlia Gràcia-Mont • Université de Bretagne Occidentale, 6 Avenue Le Gorgeu, 29287 Brest cédex, France Yves Lagabrielle Philippe Huchon Ecole Normale Supérieure, Laboratoire de Géologie, 24 Rue Lhomond, 75231 Paris cédex 05 France Manabu Tanahashi Geological Survey of Japan, 1-1-3, Higashi, Tsukuba 305, Japan ABSTRACT quired a permanent reorientation of the spreading axis during the The accretion system in the North Fyi marginal basin currently past 10 m.y. After 3 Ma, a roughly north-south accretion system consists of four major, differently oriented axes. Multibeam bathym- developed in the central and southern part of the basin, superim- etry, recently acquired over the central north-south axis between 18° posing 030°-oriented lineations interpreted as ancient fracture zones and 21°S, reveals a peculiar tectonic framework. Fanned patterns of guiding the rotation of the New Hebrides arc (Auzende et al., 1988b). the sea-floor topography at the northern and southern tips of this The accretion system currently consists of four first-order, dif- segment are the general shape of a rugby ball. These data, and the ferently oriented segments, two of which converge with a fracture interpretation of magnetic anomalies, indicate that this central sector zone having left-lateral motion to form a triple junction (Auzende et of the ridge has lengthened northward at the expense of the axis aligned al., 1988a, 1988b; Lafoy et al., 1990) (Fig.
    [Show full text]
  • A Tectonic Test of Instantaneous Kinematics of the Easter Microplate
    OCEANOLOGICA ACTA. 1990. VOL. SPÉCIAL 10 ~ ---~~ Microplate Eastcr island A tectonic test Plate kinematics Rap.ll1ui expcdition Ridge tcctonics of instantaneous kinematics of the Mic roplaquc Ile de Pâques Cinématiqu~.des plaquel! Expe<1mon Rapam.n Easter microplate Tcclomque des dorsales Janet H. ZUKIN, Jean FRANCHETEAU Inslitut de Physique du Globe, 4 Place Jussieu, 75252 Paris Cedex 05, France. Received 03/11/89, in rcviscd fonn 09/04/90, accepted 1O/O5!90. ABSTRACT Oetailed studies of the Easler microplate, and other contemporary microplates located along the world's mid-oceanic ridge system, are considered of primary importance to our understanding of the kinematic evolution of the major oceanic plates. The focus of the Rapanu i expedition, pan of the "Tour du monde" of the French research vessel Jean CluJrcol, was to collee! detailed structural and geophysical data along the nonhem and southem Easter microplate boundaries in order to test, in a rigorous manner, the most recent tectonic and kinematic models for Ihe micro plaie. ln developing detailed bathymetric, morphoteclonic and magnelic maps of Ihese boundaries, we have found lhal our new plate boundaries differ considerably from Ihose of Hey et al. (1985). These new boundaries arc characterized by complex defonnational structures, particularly at Ihe northern and soulhern triple junctions. The norlhern boundary is dominated by compression and right lateral shear, paftÎCularly to the west, and leaùs 10 extension in the east. The southem boundary is dominaled by extension, particularly
    [Show full text]
  • Subduction Controls the Distribution and Fragmentation of Earth’S Tectonic Plates Claire Mallard, Nicolas Coltice, Maria Seton, R.D
    Subduction controls the distribution and fragmentation of Earth’s tectonic plates Claire Mallard, Nicolas Coltice, Maria Seton, R.D. Müller, Paul J. Tackley To cite this version: Claire Mallard, Nicolas Coltice, Maria Seton, R.D. Müller, Paul J. Tackley. Subduction controls the distribution and fragmentation of Earth’s tectonic plates. Nature, Nature Publishing Group, 2016, 535 (7610), pp.140-143. 10.1038/nature17992. hal-01355818 HAL Id: hal-01355818 https://hal.archives-ouvertes.fr/hal-01355818 Submitted on 24 Aug 2016 HAL is a multi-disciplinary open access L’archive ouverte pluridisciplinaire HAL, est archive for the deposit and dissemination of sci- destinée au dépôt et à la diffusion de documents entific research documents, whether they are pub- scientifiques de niveau recherche, publiés ou non, lished or not. The documents may come from émanant des établissements d’enseignement et de teaching and research institutions in France or recherche français ou étrangers, des laboratoires abroad, or from public or private research centers. publics ou privés. Subduction controls the distribution and fragmentation of Earth’s tectonic plates Claire Mallard1, Nicolas Coltice1,2, Maria Seton3, R. Dietmar Müller3, Paul J. Tackley4 1. Laboratoire de géologie de Lyon, École Normale Supérieure, Université de Lyon 1, 69622 Villeurbanne, France. 2. Institut Universitaire de France, 103, Bd Saint Michel, 75005 Paris, France 3. EarthByte Group, School of Geosciences, Madsen Building F09, University of Sydney, NSW, 2006, Australia 4. Institute of Geophysics, Department of Earth Sciences, ETH Zürich, Sonneggstrasse 5, 8092 Zurich, Switzerland The theory of plate tectonics describes how the surface of the Earth is split into an organized jigsaw of seven large plates1 of similar sizes and a population of smaller plates, whose areas follow a fractal distribution2,3.
    [Show full text]
  • Telepresence-Enabled Exploration of The
    ! ! ! ! 2014 WORKSHOP TELEPRESENCE-ENABLED EXPLORATION OF THE !EASTERN PACIFIC OCEAN WHITE PAPER SUBMISSIONS ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! TABLE OF CONTENTS ! ! NORTHERN PACIFIC! Deep Hawaiian Slopes 7 Amy Baco-Taylor (Florida State University) USS Stickleback (SS-415) 9 Alexis Catsambis (Naval History and Heritage Command's Underwater Archaeology Branch) Sunken Battlefield of Midway 10 Alexis Catsambis (Naval History and Heritage Command's Underwater Archaeology Branch) Systematic Mapping of the California Continental Borderland from the Northern Channel Islands to Ensenada, Mexico 11 Jason Chaytor (USGS) Southern California Borderland 16 Marie-Helene Cormier (University of Rhode Island) Expanded Exploration of Approaches to Pearl Harbor and Seabed Impacts Off Oahu, Hawaii 20 James Delgado (NOAA ONMS Maritime Heritage Program) Gulf of the Farallones NMS Shipwrecks and Submerged Prehistoric Landscape 22 James Delgado (NOAA ONMS Maritime Heritage Program) USS Independence 24 James Delgado (NOAA ONMS Maritime Heritage Program) Battle of Midway Survey and Characterization of USS Yorktown 26 James Delgado (NOAA ONMS Maritime Heritage Program) Deep Oases: Seamounts and Food-Falls (Monterey Bay National Marine Sanctuary) 28 Andrew DeVogelaere (Monterey Bay National Marine Sanctuary) Lost Shipping Containers in the Deep: Trash, Time Capsules, Artificial Reefs, or Stepping Stones for Invasive Species? 31 Andrew DeVogelaere (Monterey Bay National Marine Sanctuary) Channel Islands Early Sites and Unmapped Wrecks 33 Lynn Dodd (University of Southern
    [Show full text]
  • Mantle Plume Capture, Anchoring, and Outflow During Galápagos
    PUBLICATIONS Geochemistry, Geophysics, Geosystems RESEARCH ARTICLE Mantle plume capture, anchoring, and outflow during 10.1002/2015GC005723 Galapagos plume-ridge interaction Key Points: S. A. Gibson1, D. J. Geist2, and M. A. Richards3 Recycled oceanic crust contributes to Galapagos Spreading Center basalts 1Department of Earth Sciences, University of Cambridge, Cambridge, UK, 2Department of Geological Sciences, University On-axis capture and anchoring of of Idaho, Moscow, Idaho, USA, 3Department of Earth and Planetary Science, University of California, Berkeley, Galapagos plume stem during ridge migration California, USA Deep melt channels may connect Galapagos plume and adjacent ridge Abstract Compositions of basalts erupted between the main zone of Galapagos plume upwelling and Supporting Information: adjacent Galapagos Spreading Center (GSC) provide important constraints on dynamic processes involved Supporting Information S1 in transfer of deep-mantle-sourced material to mid-ocean ridges. We examine recent basalts from central and northeast Galapagos including some that have less radiogenic Sr, Nd, and Pb isotopic compositions Correspondence to: than plume-influenced basalts (E-MORB) from the nearby ridge. We show that the location of E-MORB, S. A. Gibson, greatest crustal thickness, and elevated topography on the GSC correlates with a confined zone of low- [email protected] velocity, high-temperature mantle connecting the plume stem and ridge at depths of 100 km. At this site on the ridge, plume-driven upwelling involving deep melting of partially dehydrated, recycled ancient oce- Citation: Gibson, S. A., D. J. Geist, and anic crust, plus plate-limited shallow melting of anhydrous peridotite, generate E-MORB and larger amounts M. A.
    [Show full text]
  • Project XXX Acronym of the Proposal PEPS
    PROGRAMME BLANC Project XXX INTERNATIONAL DOCUMENT B EDITION 2009 Acronym of the proposal PEPS - Chile Title of the proposal in Physique des mécanismes de Tremblements de Terre French de la Subduction Andine au Chili Title of the proposal in Physics of Earthquake processes on the Andean English Subduction in Chile Theme (principal)1 1 2 3 4 5 5 6 7 8 9 Theme (secondary) 1 2 3 5 4 5 6 7 8 9 Type of research 5 Basic Research Industrial Research Experimental Development International Agency : CONYCIT Cooperation Country : Chile Total requested funding Project Duration 36 months ANR 376 781 € CONICYT 218 200 € 1 Voir comité scientifique disciplinaire en annexe 7.4 ANR‐GUI‐AAP‐02 1/78 PROGRAMME BLANC Project XXX INTERNATIONAL DOCUMENT B EDITION 2009 1. CONTEXT AND RELEVANCE TO THE CALL 2 1.1. Context, economic and societal issues .......................................................................... 2 1.2. Relevance of the proposal ........................................................................................... 3 2. SCIENTIFIC AND TECHNICAL DESCRIPTION ..................................... 5 2.1. State of the Art ......................................................................................................... 5 2.2. S & T objectives, progress beyond the state of the art .................................................... 8 3. SCIENTIFIC AND TECHNICAL OBJECTIVES / PROJECT DESCRIPTION .............................. 10 3.1. Scientific Programme, Project structure 10 Task 1 Analysis of the co- and post-seismic
    [Show full text]
  • Young Tracks of Hotspots and Current Plate Velocities
    Geophys. J. Int. (2002) 150, 321–361 Young tracks of hotspots and current plate velocities Alice E. Gripp1,∗ and Richard G. Gordon2 1Department of Geological Sciences, University of Oregon, Eugene, OR 97401, USA 2Department of Earth Science MS-126, Rice University, Houston, TX 77005, USA. E-mail: [email protected] Accepted 2001 October 5. Received 2001 October 5; in original form 2000 December 20 SUMMARY Plate motions relative to the hotspots over the past 4 to 7 Myr are investigated with a goal of determining the shortest time interval over which reliable volcanic propagation rates and segment trends can be estimated. The rate and trend uncertainties are objectively determined from the dispersion of volcano age and of volcano location and are used to test the mutual consistency of the trends and rates. Ten hotspot data sets are constructed from overlapping time intervals with various durations and starting times. Our preferred hotspot data set, HS3, consists of two volcanic propagation rates and eleven segment trends from four plates. It averages plate motion over the past ≈5.8 Myr, which is almost twice the length of time (3.2 Myr) over which the NUVEL-1A global set of relative plate angular velocities is estimated. HS3-NUVEL1A, our preferred set of angular velocities of 15 plates relative to the hotspots, was constructed from the HS3 data set while constraining the relative plate angular velocities to consistency with NUVEL-1A. No hotspots are in significant relative motion, but the 95 per cent confidence limit on motion is typically ±20 to ±40 km Myr−1 and ranges up to ±145 km Myr−1.
    [Show full text]
  • Across-Arc Geochemical Variations in the Southern Volcanic Zone, Chile (34.5–38.0°S): Constraints on Mantle Wedge and Slab Input Compositions
    Available online at www.sciencedirect.com Geochimica et Cosmochimica Acta 123 (2013) 218–243 www.elsevier.com/locate/gca Across-arc geochemical variations in the Southern Volcanic Zone, Chile (34.5–38.0°S): Constraints on mantle wedge and slab input compositions G. Jacques a,⇑, K. Hoernle a,b, J. Gill c, F. Hauff b, H. Wehrmann a, D. Garbe-Scho¨nberg d, P. van den Bogaard a,b, I. Bindeman e, L.E. Lara f a Collaborative Research Center (SFB574), University of Kiel and GEOMAR, 24148 Kiel, Germany b GEOMAR Helmholtz Centre for Ocean Research Kiel, 24148 Kiel, Germany c University of California, Santa Cruz, CA 95064, USA d Institute of Geosciences of the University of Kiel, 24118 Kiel, Germany e University of Oregon, Eugene, OR 97403, USA f Servicio Nacional de Geologı´a y Minerı´a, Santiago, Chile Received 7 September 2012; accepted in revised form 13 May 2013; available online 23 May 2013 Abstract Crustal assimilation (e.g. Hildreth and Moorbath, 1988) and/or subduction erosion (e.g. Stern, 1991; Kay et al., 2005) are believed to control the geochemical variations along the northern portion of the Chilean Southern Volcanic Zone. In order to evaluate these hypotheses, we present a comprehensive geochemical data set (major and trace elements and O–Sr–Nd–Hf–Pb isotopes) from Holocene primarily olivine-bearing volcanic rocks across the arc between 34.5°S and 38.0°S, including volcanic front centers from Tinguiririca to Callaqui, the rear arc centers of Infernillo Volcanic Field, Laguna del Maule and Copahue, and extending 300 km into the backarc.
    [Show full text]
  • Geologic and Structural Evolution of the NE Lau Basin, Tonga: Morphotectonic Analysis and Classification of Structures Using Shallow Seismicity
    ESSOAr | https://doi.org/10.1002/essoar.10502463.2 | CC_BY_NC_ND_4.0 | First posted online: Mon, 8 Feb 2021 12:42:39 | This content has not been peer reviewed. Geologic and Structural Evolution of the NE Lau Basin, Tonga: Morphotectonic Analysis and Classification of Structures using Shallow Seismicity 1 Melissa O. Anderson1†, Chantal Norris-Julseth1†, Kenneth H. Rubin2, Karsten Haase3, Mark D. 2 Hannington4,5, Alan T. Baxter4, and Margaret S. Stewart6 3 1Department of Earth Sciences, University of Toronto, 22 Ursula Franklin Street, Toronto, Ontario, 4 M5S 3B1, Canada 5 2Department of Geology and Geophysics, SOEST, University of Hawaii, 1680 East-West Road, 6 Honolulu, Hawaii, 96822, USA 7 3GeoZentrum Nordbayern, Friedrich-Alexander University of Erlangen-Nürnberg, Schlossgarten 5, 8 D-91054 Erlangen, Germany 9 4Department of Earth Sciences, University of Ottawa, 25 Templeton, Ottawa, Ontario, K1N 6N5, 10 Canada 11 5GEOMAR, Helmholtz Centre for Ocean Research Kiel, Wischhofstrasse 1-3, 24148 Kiel, Germany 12 6Department of Earth and Environmental Sciences, Mount Royal University, 4825 Mount Royal Gate 13 SW, Calgary, Alberta, T3E 6K5, Canad 14 * Correspondence: 15 Melissa O. Anderson: [email protected] 16 Keywords: NE Lau Basin, backarc basin, geologic mapping, morphotectonic, submarine volcanism, 17 shallow seismicity, fault kinematics, Riedel megashear, hydrothermal systems, 18 Abstract 19 The transition from subduction to transform motion along horizontal terminations of trenches is 20 associated with tearing of the subducting slab and strike-slip tectonics in the overriding plate. One 21 prominent example is the northern Tonga subduction zone, where abundant strike-slip faulting in the 22 NE Lau back-arc basin is associated with transform motion along the northern plate boundary and 23 asymmetric slab rollback.
    [Show full text]
  • Geochemical Variations in the Central Southern Volcanic Zone, Chile (38- 43◦S): the Role of fluids in Generating Arc Magmas
    ÔØ ÅÒÙ×Ö ÔØ Geochemical variations in the Central Southern Volcanic Zone, Chile (38- 43◦S): The role of fluids in generating arc magmas G. Jacques, K. Hoernle, J. Gill, H. Wehrmann, I. Bindeman, Luis E. Lara PII: S0009-2541(14)00056-4 DOI: doi: 10.1016/j.chemgeo.2014.01.015 Reference: CHEMGE 17134 To appear in: Chemical Geology Received date: 2 September 2013 Revised date: 20 January 2014 Accepted date: 27 January 2014 Please cite this article as: Jacques, G., Hoernle, K., Gill, J., Wehrmann, H., Bindeman, I., Lara, Luis E., Geochemical variations in the Central Southern Volcanic Zone, Chile (38-43◦S): The role of fluids in generating arc magmas, Chemical Geology (2014), doi: 10.1016/j.chemgeo.2014.01.015 This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. ACCEPTED MANUSCRIPT Geochemical variations in the Central Southern Volcanic Zone, Chile (38-43°S): The role of fluids in generating arc magmas G. Jacques1*, K. Hoernle1,2, J. Gill3, H. Wehrmann1, I. Bindeman4, Luis E. Lara5 1Collaborative Research Center (SFB574), University of Kiel and GEOMAR, 24148 Kiel, Germany 2GEOMAR Helmholtz Centre for Ocean Research, 24148 Kiel, Germany 3University of California, Santa Cruz CA 95064, USA 4University of Oregon, Eugene OR 97403, USA 5Servicio Nacional de Geología y Minería, Santiago, Chile *Corresponding author: Dr.
    [Show full text]
  • A Grand Tour of the Ocean Basins by Declan G
    Transforms and fracture zones are introduced, also abandoned basins, convergent boundaries, and marginal basins. Instructors can easily change the sequence of stops to suit their courses using the Google Earth desktop app or by editing the KML file.Because large placemark balloons tend to obscure the Google Earth terrain behind them, you are advised to keep Google Earth and this PDF document open in separate windows, preferably on separate monitors or devices. Fig. 0 caption acknowledges all data and imagery sources. A Grand Tour of the Ocean Basins by Declan G. De Paor, [email protected] Welcome to the Grand Tour of the Ocean Basins! Use this document in association with the Google Earth tour which you can download from http://geode.net/GTOB/GTOB.kml Ocean floor ages are from http://nachon.free.fr/GE, based on Müller et al. (2008). See earthbyte.org/Resources/agegrid2008.html. Plate boundaries are from Laurel Goodell’s SERC web page: http://serc.carleton.edu/sp/library/google_earth/examples/ 49004.html based on Bird (2003) and programmed by Thomas Chust. Colors and line sizes were changed to improve visibility for persons with color vision deficiency, and I added other minor adjustments. The Tour Stops are arranged in a teaching sequence, Fig. 0. Plate Tectonics on Google Earth. ©2017 Google starting with continental rifting and incipient ocean basin Inc. Data SIO, NOAA, US Navy, NGA, USGS, GEBCO, formation in East Africa and the Red Sea and ending with NSF, LDEO, NOAA. Image Landsat/Copernicus, IBCAO, the oldest surviving fragments of oceanic crust. PGC, LDEO-Columbia.
    [Show full text]
  • Noble Gas Isotope Geochemistry of Mid-Ocean Ridge and Ocean Island Basalts: Characterization of Mantle Source Reservoirs
    Noble Gas Isotope Geochemistry of Mid-Ocean Ridge and Ocean Island Basalts: Characterization of Mantle Source Reservoirs David W. Graham College of Oceanic & Atmospheric Sciences Oregon State University Corvallis, OR 97331 pp. 247-318 Noble Gases in Geochemistry and Cosmochemistry D. Porcelli, C.J. Ballentine and R. Wieler (editors) Reviews in Mineralogy and Geochemistry Mineralogical Society of America Washington, DC August 2002 Noble Gas Isotope Geochemistry of Mid-Ocean Ridge and Ocean Island Basalts: Characterization of Mantle Source Reservoirs David W. Graham College of Oceanic & Atmospheric Sciences Oregon State University Corvallis, Oregon 97331 [email protected] INTRODUCTION The study of noble gases in oceanic basalts is central to understanding chemical heterogeneity of the Earth’s mantle and origin of the atmosphere. In the terrestrial environment the abundances of noble gases are quite low because they were excluded from solid materials during planetary formation in the inner solar system. This low background inventory helps to make the noble gases excellent tracers of mantle reservoirs. In this context, mid-ocean ridge and ocean island basalts provide valuable windows into the Earth’s mantle. These oceanic basalts are not prone to the degree of contamination often observed in continental lavas that results from their passage through thick continental lithosphere and crust. Mid-ocean ridge basalts (MORBs) form by partial melting as the ascending mantle beneath spreading ridges reaches its solidus temperature, and MORBs are generally accepted to represent a broad sampling of the convecting upper mantle. Ocean island basalts (OIBs) represent melting ‘anomalies’ that are generally related to mantle upwelling. The extent to which ocean islands are derived from a thermal boundary layer in the deep mantle (e.g., as a mantle plume) or from chemical heterogeneities embedded within the mantle convective flow (e.g., as a mantle ‘blob’) has been debated for decades, and is not currently resolved.
    [Show full text]